1. Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to enhancing data retransmission to improve call performance.
2. Background
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.
For example, as per the radio link control (RLC) layer protocol, whenever a user equipment (UE) (or other message-transmitting device, such as a Node B) receives a RESET command from a peer RLC entity, which may be a message-receiving device (such as a UE or network entity, e.g., a Node B or radio network controller), the UE will discard all previously transmitted protocol data units (PDUs). The UE may store these previously transmitted PDUs, which may be part of a larger service data unit (SDU), in a buffer when they have not yet been acknowledged as having been received by a receiving entity. Additionally, the UE discards any portions of partially-transmitted SDUs pending in a transmission queue at the UE (e.g., some PDUs of the SDU have been transmitted and some PDUs of the SDU are pending transmission in the transmission queue). After completion of this discarding procedure, the UE resumes transmission, starting with an SDU that came after the discarded SDU in the transmission queue. As such, an SDU, or PDUS of the SDU, may be lost.
Furthermore, when a message is transmitted in the uplink (UL) and a radio link control (RLC) re-establishment indication is concurrently received in the downlink (DL), the transmitted message and associated PDUs are discarded. Though the RLC protocol layer indicates the failure of the signaling message to a radio resource controller (RRC), the RRC does not include instructions for recovery of the transmitted message. As a result, the lost signaling message is not retransmitted by the RLC or upper layers. This can lead to a deadlock in the signaling procedure such that subsequent SDUs are not processed by a receiver. In some instances, this will lead to call release.
Thus improvements in message and data transmission in communications networks to avoid lost messages, data, and call release are desired.